Shoe shank reinforcement



Aug. 30, 1955 H. c. STEIN 2,716,296

SHOE SHANK REINFORCEMENT Filed March l5, 1952 .L .4. l El l @a 67 TL; @6 69 INVENTOR ATTORNEY United StatesA Patent wOffice 2,716,2 96 Patented Aug. `30, 1955 SHOE SHAN K REINFORCEMEN'I Harry Charles Stein, Yonkers, N. Y., assignor of ouefifth to Leonard J. Stein, Houston, Tex., `one-fifth to Stanley M. Stein, New Orleans, La., one-fifth to Melvin Stein, Jackson Heights, and `one-fifth to Frank `R. Stein, Yonkers, N. Y.

Application March 15, 1952, Serial'No. 276,753

3 Claims. `(Cl. 36--76) `My invention relates to shoes and more particularly to the `Shanks thereof.

Asiappears in my earlier patent application No.`247,`245, `dated September l5, `195-1, -now Pat. No. 2,648,144, dated Aug. 11, 1953, the distribution of the forces in the foot, when standing or in propulsion, occurs along different axes. The axis of standing, for example, extends along a longitudinal line from the under surface of the center of the heel bone, i. e. the medial calcaneal tubercle, to the head of the third metatarsal bone. The axis of propulsion extends along an oblique axis from the center of the heel bone to the ball of the large toe. The various motions involved in the changes of position and form of the foot include axial torsion, abduction and adduction of the forefoot, pronation and supination, inversion and eversion, plantar and dorsiflexion, as well as changes in the length of the foot.

One of the major requirements of `the shank or arch support of the shoe is to allow the shifting of the body weight from the axis of standing to the axis of propulsion, and the return shift without interference, obstruction or delay. The foot cannot function naturally, I have discovered, unless the shank or support possesses a mobility and an adaptability of a self-adjusting character to conform with the changing requirements of the foot.

The shank of the conventional shoe consists of several layers of leather or similar material reinforced by a rigid immobile layer usually of steel, fastened between leather layers in an arbritary and symmetrical axis. Such rigid and immobile shank results in faulty weight bearing and distribution with resulting symptoms. This is followed by a structural breakdown of the foot as well as irregular premature wear of the shoe.

Accordingly the primary object of my invention is to provide a self-adjusting reinforcement for a shoe shank that supports and allows adequate transfer and distribution of the body weight both in standing and in walking positions.

Further objects are to provide such a shank reinforcement that is capable of mobility, adaptability and realignment to the changes in the axes assumed by the foot; to provide specically for a shoe reinforcement that will permit a torsional motion in the supporting structure; and to accomplish all the foregoing features in a shank incorporated in the shoe itself, or independently in a separate arch support.

I accomplish these and other objects and obtain my new results as will be apparent from the device described in the following specification, particularly pointed out in the claims, and illustrated in the accompanying drawing in which:

Fig. l is a partial plan view of a shoe sole, the upper shown in section, illustrating in dotted lines, my self adjusting shank reinforcement.

Fig. 2 is an enlarged longitudinal sectional View of the same taken in the plane 2-2 of Fig. l.

Fig. 3 is an enlarged sectional View of a rubber ball and socket modification.

`socket seats 36, `38 Yfor `the `ball bearings.

Fig. 4 is a similar view of a sheet metal ball modification.

In the drawing reference numeral 10 designates a shoe, provided with a `shank 12 containing my improved reinforcement 14. This comprises preferably a plurality of steel .blades 16 and 18 extending longitudinally of the shoe .in :side by side arrangement, terminating at .their proximal ends in cylindrically shaped stems 20 and `22 respectively.

The `stems `are slidably supported in ball bearings 24 and 26, containing central bores 28 and 341) extending therethrough. The support `or race 31 for the `bearings `may consist of upper and lower plates 32 and 34, containing The `plates may be secured together and to the shoe by the screws 39.

The support is 4fixedly secured within .two `layers 40 and 42 of leather or similar material, which are recessed as at 43 and 45 forming a compartment to receive the reinforcement. The distal portions of the blades are slotted as at 44 and 46 and guide pins 48 and 50 slidably hold the blades in position at the slots to the shoe. An enlarged sectional View of the proximal end of the blade 18, stem 22, ball 26, and socket 36, 38 is shown in Fig. 2. The remaining space in the compartment may be filled with cork filler 51.

The support comprising the race and bearings forms a universal joint at the junction of the heel section 52 with the shank 12. The stems 20 and 22 are slidably mounted in the bores 28 and 30 of the ball bearings which permits a sliding motion of the blades. This sliding motion in addition to the rotary motion, provides .for variations in length and form assumed by the foot in its various positions of function. Suflcient clearance exists between the heads of guide pins 48 and 50 and the blades, in the modification illustrated in Figs. l and 2, so as to permit the desired movement of the blades without obstruction.

By means of twin blades, I obtain a more uniform distribution of weight than is achieved by a single blade, which may be used alternatively.

I have found that for the average adult, the blades may move longitudinally a distance of about 1A of an inch.

The length of slots 44 and 46 and the stems 20 and 22 should be suicient to accommodate this movement. The balls and sockets may have a diameter of 5/16 inch, and the stem a diameter of about 1/e inch with the bore in the ball of suttcient diameter to allow the stem to move freely therein. The stems may be sufliciently long to pass entirely through the ball.

The ball 54 of Fig. 3 may be made of resilient rubber and bonded to the stem 56, the rubber giving way Suthciently under pressure of the stem to achieve an effect similar to the ball and socket joint.

The ball and socket arrangement may be achieved entirely by stamped sheet metal parts, as is shown in Fig. 4, where the end of a blade 60 is stamped into a leaf form 62 which can be rounded into the approximate shape of a ball 64. The longitudinal movement of the end of the blade is accommodated in the socket 66 which is secured, as by brazing 67 to the underside of plate 68. The end 69 of the socket 66 provides a stop to prevent accidental separation of ball and socket.

An added benefit to be derived from rny invention is the massaging and exercising effect upon the foot by the torsional and other movements obtained during locomo- In the foregoing I have disclosed a shoe shank reinforcement that substantially maintains the supporting quality of the shank, while at the same time accommodates the body-weight shifting from the axis of standing to the axis of propulsion. The reinforcement is self adjusting both longitudinally and torsionally without loss of stability.

I have thus overcome the diculties hitherto encountered in the conventional shoe which obstructed the transfer of force to the big toe involved in propulsion and resulted in an overstrain and breakdown of the various parts of the foot 'as evidenced by broken down anterior arches, bunions, and arch strain.

I 'have thus described my invention, but I desire it understood that it is not confined to the particular forms or uses shown and described, the same being merely illustrative, and that the invention may be carried out in other Ways without departing from the spirit of my invention, and, therefore, I claim broadly the right to employ all equivalent instrumentalities coming within the scope of the appended claims, and by means of which, objects of my invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of the many that can be employed to attain these objects and accomplish these results.

What I claim and desire to secure by Letters Patent, is as follows:

l. A shoe shank reinforcement comprising a shaperetaining element extending from the region of the breast of the heel of the shoe for the length of the shank area and a proximal support therefor carried by the heel section of the shoe and having means supporting the rear end of the shape-retaining element for torsional movement along its longitudinal axis, whereby torsional movement of the foot in the shank area is unimpeded by the reinforcement during dynamic action of the foot.

2. The device of claim 1 wherein the proximal end of the shape-retaining element is mounted universally with respect to the proximal support.

3. The device of claim 1 wherein a plurality of elements and corresponding proximal supports are provided.

References Cited in the le of this patent UNITED STATES PATENTS 1,877,525 Monaghan Sept. 13, 1932 1,885,259 Hirshfield Nov. l, 1932 1,940,941 Dettlebach Dec. 26, 1933 2,295,364 Skorepa Sept. 8, 1942 

